Ms. Elleen Hsu recently presented a poster entitled “Insulation Usage and Asbestos Exposures: Historical Trends and Exposure Assessment” at the 2017 International Society of Exposure Science Meeting held in Durham, North Carolina. The purpose of this research was to identify factors that impacted the trends of historical airborne asbestos concentrations from insulation products and to model how these factors would affect human exposures. The authors found that airborne fiber concentrations measured during insulation work in shipyards were 3.5 to 15.5 times higher than concentrations measured for similar tasks in non-shipyard settings. The authors also modeled asbestos exposure estimates for full-shift insulators using task-specific frequencies and concentrations reported in the literature. Using our model, a cumulative occupational exposure for an insulator could be estimated by summing the cumulative exposure for the years of interest. Additionally, our research also found that asbestos concentrations declined over time, likely driven by the passage of the OSH Act and subsequent PEL rulings, as well as advancements in asbestos research and industrial hygiene practices.

As a follow up to last week's blog, Bethany Winans answered a few questions regarding her upcoming SOT presentation:

1. What's the title of your presentation and when is the presentation/poster session?

QSAR Modeling Toxicity Predictions of the Constituents of Crude 4-Methylcyclohexanemethanol (MCHM) and Structurally Related Chemical. Bethany will present on Monday, March 14th in the afternoon session

2. What was the scope of your research?

Approximately two years ago, a mixture containing crude MCHM was accidentally released into the Elk River in West Virginia, affecting the drinking water supply of ~300,000 people. We used quantitative structure-activity-relationship ((Q)SAR) modeling and structural alerts to predict the toxicity of the constituents of crude MCHM and other structurally related chemicals. For those constituents for which toxicity data exist, we compared the (Q)SAR predictions to the toxicity data to assess the applicability of the models for these compounds.

3. What did you find?

Overall, the constituents of crude MCHM and structurally related compounds were predicted to have low to moderate acute toxicity, low potential for skin and eye irritation, and low mutagenic potential; these findings are consistent with available toxicity data. Some of the chemicals were predicted to have the potential to be skin sensitizers or associated with developmental toxicity, but these predictions were not supported by the animal data, suggesting that the models may not be valid for predicting these endpoints for these chemicals. Predictions from (Q)SAR modeling and experimental data for the constituents of crude MHCM and structurally related compounds suggest that these chemicals pose little risk to human health at concentrations likely experienced following the Elk River spill.

4. What the next steps/what other research is needed?

Following the Elk River spill, the National Toxicology Program (NTP) performed a number of toxicity tests on crude MCHM and its constituents. The NTP recently completed these studies, and noted that "[th]e collected findings from the studies supported the adequacy of the drinking water screening levels established at the time of the spill [1 ppm in water], and found very little reason for concern about long-term health effects" (West Virginia Chemical Spill: NTP Research Response and Findings, February 2016, p. 1).

This type of predictive toxicological evaluation can be used in other situations as well. (Q)SAR modeling can be used to predict the toxicity of a number of compounds, and provides a rapid screening-level assessment to identify potential toxicological endpoints for chemicals of concern.

As in previous years, a group of researchers from Cardno ChemRisk will attend the 2016 Society of Toxicology's Annual Meeting in New Orleans from March 13-17. At SOT, we will present recent research during posters and presentations.

Between today and the start of the conference, the Cardno ChemRisk View will feature a series of presentations, as described by staff (you can read the 2015 entries here and here). First up is Lindsey Garnick from our San Francisco office:

A group of researchers from Cardno ChemRisk will attend the 2015 Society of Toxicology's Annual Meeting in San Diego, California from March 22-26. At SOT, we will present recent research during posters and presentations.

The Cardno ChemRisk View

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Cardno ChemRisk is a respected scientific consulting firm headquartered in San Francisco with locations and consultants across the U.S. While our website provides a formal look at our capabilities, the Cardno ChemRisk View provides an informal voice too. Various Cardno ChemRisk consultants will be sharing news and views about current trends, happenings and methodologies in the industry. We’ll also highlight activities of interest at Cardno ChemRisk, within confidentiality restrictions of course.

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